I wonder what other possibilities there are though.. some of the new people hooked up hundreds of computers (someone said 300 workstations?) so the network adjusted difficulty. To give you some perspective, in all the time it has been running the difficulty rose to 23. The previous jump was very large, it went from 19 to 23. When all the new users showed up it jumped from 23 to 45. It's based on fast the new blocks are showing up, if they're being generated very quickly then the difficulty jumps accordingly to target 1 block every 10 mins average.
Again, this is a problem with the algorithm that needs to be fixed if it is to scale to any appreciable size. So apparently some users are devoting a significant amount of CPU resources to generate coins, and view this as the early days of a gold rush. That should have been anticipated based on the number of topics on this forum alone that has discussed this issue.
In terms of packet collisions, that is a topic that has been dealt with exhaustively in terms of studies of ethernet packets, and I think the same principles apply. Certainly if there is a collision and one person gets a new coin block added but a second person doesn't, there ought to be some sort of "resend" or "reattempt" algorithm to add that coin block as the proof of work clearly can be demonstrated. Yes, there are extreme limits that get close to bandwidth limits where collision becomes typical until the network simply shuts down from collisions.
Again, please correct me if I'm wrong here, but this is an issue with having a single coin chain that keeps track of all potential blocks. Perhaps that is the wrong way to think about it, and this could be a route for some multi-tiered efforts as well. What if there was an initial coin block that was cryptographically very difficult to make (but not impossible) worth a fairly substantial amount (say 100 or 1000 BCs) and then associated sub-blocks tied to that are worth smaller amounts (say 1 BC or even 0.01 BCs) that can be linked to each new chain that are computationally trivial in comparison. Collisions would only happen if two people tried to add two blocks onto the same chain, thus reducing the potential for collisions. Adding to the "main" chain would also have a reduced collision frequency due to the fact that most "new" users aren't generating those kind of blocks and due to the CPU time necessary to create them in the first place. This is something that could even be extended to a "third" dimension for even a tertiary level of new coin block linked to the secondary blocks.
The purpose is to avoid collisions, not to keep people from generating the coins or devaluing those coins which already exist. This is also but one other alternative idea on what might be able to be done here.